Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Double chemical action yields double success

19.03.2012
The dynamic equilibrium between two reactive silicon compounds provides chemists with improved tools for synthesizing optically and electronically active molecules

Molecules containing silicon double bonds, or disilenes, can be nearly twice as responsive to light as double-bonded hydrocarbons—a feature that makes them irresistible to researchers developing novel devices such as organic light-emitting diodes.


A cross-over reaction between dibromo-disilene compounds substituted with two types of ‘Rind’ ligands (red and blue spheres) can take place at room temperature in solution without using metal catalysts (yellow spheres, bromine). Copyright : 2012 Tsukasa Matsuo et al.

But because disilenes are difficult to isolate and tend to polymerize, chemists struggle to control them with their usual synthetic tricks. Now, Kohei Tamao and colleagues from the RIKEN Advanced Science Institute in Wako have discovered a unique halogen-substituted disilene complex that makes assembling advanced conjugated materials easier than ever before.

Halogen elements such as chlorine or bromine can boost the synthetic capabilities of many molecules once attached to their frameworks. Techniques known as substitution reactions can then switch the halogens for other groups, such as aromatic species. However, chemists have scarcely studied halogenated disilenes because theoretical calculations indicate that they are inherently volatile.
Recently however, Tamao and colleagues developed compounds that are extraordinarily adept at stabilizing disilenes. Known as ‘Rind’ ligands, these molecules have a unique fused-ring structure that locks silicon double bonds into place. They also have chemically tunable side chains that optimize compatibility with a variety of substrates and solvents. Based on these capabilities, Tamao and team postulated that their technique could capture the halogenated targets.

Experiments proved that their instincts were correct: combining a Rind-protected bromine–silicon precursor with a reducing agent successfully produced the sought-after dibromo-disilene crystals. But closer examination of the new product’s reactivity revealed a surprise. Simply mixing it with an acetylene derivative caused the disilene to cleave in half and join to both sides of the carbon triple bond, producing a triangle-shaped unsaturated ring.

According to co-author Tsukasa Matsuo, this reaction provided strong evidence that the halogenated disilene could easily dissociate. To confirm this behavior, Katsunori Suzuki, another co-author, dissolved two dibromo-disilenes, each protected by a different Rind ligand, into solution. After one day at room temperature, the researchers observed an extraordinary event: the spontaneously cleaved fragments, known as bromo-silylenes, had reconnected into new disilenes containing both Rind ligands (Fig. 1). This type of ‘cross-over’ reaction, also known as olefin metathesis, is extremely useful to chemists and normally requires expensive metal catalysts to proceed.

The researchers exploited the synthetic potential of the dynamic dibromo-disilenes by capturing the reactive silylene fragment with a base, and then used this complex to construct aromatic-substituted conjugated silicon molecules inaccessible through other techniques. “These results open a new platform for development of functional disilene materials and devices,” says Matsuo.

The corresponding author for this highlight is based at the Functional Elemento-Organic Chemistry Unit, RIKEN Advanced Science Institute

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Life Sciences:

nachricht Rutgers scientists discover 'Legos of life'
23.01.2018 | Rutgers University

nachricht Researchers identify a protein that keeps metastatic breast cancer cells dormant
23.01.2018 | Institute for Research in Biomedicine (IRB Barcelona)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Rutgers scientists discover 'Legos of life'

23.01.2018 | Life Sciences

Seabed mining could destroy ecosystems

23.01.2018 | Earth Sciences

Transportable laser

23.01.2018 | Physics and Astronomy

VideoLinks Science & Research
Overview of more VideoLinks >>>